The present invention relates to head-worn apparatus including an optical device adjustably coupled thereto, and to coupling apparatus for adjustably securing the optical device.
Head-worn binocular ophthalmoscopes essentially include two components, an optical unit and a headband. A known headband comprises a lower, annular band enclosing the top of the head and an upper, semi-circular band laterally connected thereto. Both bands are flexible and may be made of plastic, and can be adjusted to the size and shape of the examiner's head by means of adjusting devices. The optical unit is attached directly to the front side of the lower band by an adjustable coupling device which permits the examiner to adjust the height, distance and inclination of the optical unit in relation to his or her eyes, so as to optimally position the optical device relative to the examiner's eyes. However, the headband is typically removed by the examiner when the optical unit is not being used and the examiner wishes to completely clear his or her field of view, even during the course of an examination.
In another head-worn binocular ophthalmoscope, the optical unit is not attached directly to the headband, but to an approximately semi-circular metal bow by means of an adjusting device. The sides of the bow are pivotally attached to the headband so the bow can be laterally pivoted on the headband. The pivoting arrangement for each side of the bow includes a rotatable knob, each of which must be tightened to lock the bow and loosened to move the bow. The bow is thus capable of being pivoted on the headband and locked in a pivoted position by the knobs. To use the optical unit, the bow is lowered and locked by the knobs in a viewing position of the optical unit and the optical unit is adjusted relative to the bow for optimal viewing. When the examiner wishes to move the optical unit out of his or her field of view, the bow is unlocked, swung upwardly completely out of the examiner's field of view and locked again. This arrangement has the advantage that the examiner does not have to take the headband off while pausing during an examination and then replace it in order to continue with the examination. A disadvantage, however, with this headband arrangement is that the knobs must be loosened and tightened for each upward and downward swivelling of the bow with attached optical unit in order to move it from one position to another, and the bow and/or the adjusting device has to be readjusted to exactly position the optical unit in the viewing position each time the bow is swivelled, so as to provide the examiner with optimal viewing conditions.